DNA fingerprinting of lactic acid bacteria in sauerkraut fermentations

Abstract

Previous studies using traditional biochemical identification methods to study the ecology of commercial sauerkraut fermentations revealed that four species of lactic acid bacteria, Leuconostoc mesenteroides, Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus brevis, were the primary microorganisms in these fermentations. In this study, 686 isolates were collected from four commercial fermentations and analyzed by DNA fingerprinting. The results indicate that the species of lactic acid bacteria present in sauerkraut fermentations are more diverse than previously reported and include Leuconostoc citreum, Leuconostoc argentinum, Lactobacillus paraplantarum, Lactobacillus coryniformis, and Weissella sp. The newly identified species Leuconostoc fallax was also found. Unexpectedly, only two isolates of P. pentosaceus and 15 isolates of L. brevis were recovered during this study. A better understanding of the microbiota may aid in the development of low-salt fermentations, which may have altered microflora and altered sensory characteristics.

FIG. 1.

Biochemistry of the Y1 fermentation. Changes in the concentrations of acids and sugars during the first 14 days after the start of the Y1 fermentation are shown. Symbols: ○, lactic acid; ⋄, acetic acid; ▵, mannitol; □, glucose; ▿, fructose.

FIG. 2.

Changes in gas production by microorganisms during commercial sauerkraut fermentations. The percentages of total isolates that were heterofermentative (A) or homofermentative (B) on each day (days 1, 3, 7, and 14) for each of the four commercial fermentations sampled are shown. T, tank.

FIG. 3.

Microbial diversity of the Y1 fermentation as determined by ITS-PCR and 16S rRNA gene sequencing. The percentages of the total isolates (95, 93, 93, and 90 isolates on days 1, 3, 7, and 14, respectively) that were members of different species are indicated by the bars.

FIG. 4.

Microbial diversity of the Y2 fermentations as determined by ITS-PCR and 16S rRNA gene sequencing. The percentages of the total isolates (95, 93, 93, and 90 isolates on days 1, 3, 7, and 14, respectively) that were members of different species are indicated by the bars. The results for tank 1 (A), tank 2 (B), and tank 3 (C) are shown.